Vehicle gear boxes are used to transfer a driving input from a vehicle engine to a driving output to one or more drive axles. Gearboxes such as transmissions and transfers cases for example, include an internal gear drive that can provide a desired gear ratio configuration to provide a desired output speed/torque for the drive axles. Typically, a transfer case includes an input shaft that receives the driving input and a pair of output shafts that are configured to drive front and rear drive axles. The gear drive transfers the driving input from the input shaft to the pair of output shafts.
Transmissions and transfer cases are often equipped with a power take-off (PTO) device that is used to drive a secondary device such as a pump, compressor, or generator. The PTO may include a clutch assembly that allows the PTO to be disengaged from the secondary device when the secondary device is not in use. It is desirable to have the ability to engage the clutch “on the fly”, i.e. during vehicle operation, when operation of the secondary device is needed. Traditionally, clutches that are able to engage “on the fly” are complex and expensive. It would be desirable to utilize a simple and inexpensive mechanical clutch but such mechanism are not conducive to engaging “on the fly.”